[PATCH v4 14/16] rpmsg: char: introduce a RPMsg driver for the RPMsg char device

From: Arnaud Pouliquen
Date: Wed Feb 17 2021 - 08:38:01 EST


A RPMsg char device allows to probe the endpoint device on a remote name
service announcement. With this patch the /dev/rpmsgX interface is created
either by a user application or by the remote firmware.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxxxxxxx>
---
drivers/rpmsg/rpmsg_char.c | 63 +++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 66dcb8845d6c..d5aa874865f7 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -28,6 +28,8 @@

#define RPMSG_DEV_MAX (MINORMASK + 1)

+#define RPMSG_CHAR_DEVNAME "rpmsg-raw"
+
static dev_t rpmsg_major;
static struct class *rpmsg_class;

@@ -408,6 +410,51 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent
}
EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);

+static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_channel_info chinfo;
+ struct rpmsg_eptdev *eptdev;
+
+ memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME));
+ chinfo.src = rpdev->src;
+ chinfo.dst = rpdev->dst;
+
+ eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo);
+ if (IS_ERR(eptdev) && rpdev->ept) {
+ rpmsg_destroy_ept(rpdev->ept);
+ return PTR_ERR(eptdev);
+ }
+
+ /* Set the private field of the default endpoint to retrieve context on callback. */
+ rpdev->ept->priv = eptdev;
+
+ return 0;
+}
+
+static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
+{
+ int ret;
+
+ ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
+ if (ret)
+ dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
+}
+
+static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
+ { .name = RPMSG_CHAR_DEVNAME },
+ { },
+};
+
+static struct rpmsg_driver rpmsg_chrdev_driver = {
+ .probe = rpmsg_chrdev_probe,
+ .remove = rpmsg_chrdev_remove,
+ .id_table = rpmsg_chrdev_id_table,
+ .callback = rpmsg_ept_cb,
+ .drv = {
+ .name = "rpmsg_chrdev",
+ },
+};
+
static int rpmsg_chrdev_init(void)
{
int ret;
@@ -422,9 +469,23 @@ static int rpmsg_chrdev_init(void)
if (IS_ERR(rpmsg_class)) {
pr_err("failed to create rpmsg class\n");
unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
- return PTR_ERR(rpmsg_class);
+ ret = PTR_ERR(rpmsg_class);
+ goto free_region;
}

+ ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
+ if (ret < 0) {
+ pr_err("rpmsg raw: failed to register rpmsg driver\n");
+ goto free_class;
+ }
+
+ return 0;
+
+free_class:
+ class_destroy(rpmsg_class);
+free_region:
+ unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
+
return ret;
}
postcore_initcall(rpmsg_chrdev_init);
--
2.17.1